The following applies to the USA only. For other countries -- refer to the governing communications authority.

On May 15, 1996, the United States Federal Communications Commission created the Family Radio Service (FRS) in the 462 and 467 MHz spectrum.
FRS uses narrowband FM (NBFM) with maximum effective radiated power of 0.5 watt. The service is intended for hand-held, short-range local communications. No license is required.
The average effective range of an FRS handheld varies depending on several factors but is about 3/4 to 2 mile.Be sure to read the FCC rules that pertain to FRS station operation -- see URL:
FCC RULES FOR FRS
-- Click Here